The incidence of depression has skyrocketed in children and adults since World War II. Depression affects about 10 percent of the population in the United States, and the World Health Organization predicts that by 2030 more people will suffer from depression than any other medical condition.
Antidepressant medication use has also increased (to the tune of 400 percent) since the 1980s, when drugs such as Prozac hit the market, even though recent data suggest that these medications offer little if any benefit to people with mild to moderate depression.
Despite this, the Centers for Disease Control and Prevention reported in 2011 that 11 percent of Americans over the age of 12 take antidepressants.
Why has there been such a dramatic increase in depression?
Although traumatic life events, stress and social isolation can increase the risk of depression, our Western way of life is probably a bigger contributor. Evidence suggests that nutrient-poor diets high in refined carbohydrates and commercially raised animal foods, combined with lack of exercise, all contribute to obesity, heart disease and diabetes.
These diseases are associated with elevated levels of inflammatory markers in the blood such as C-reactive protein, and they are also all associated with depression. People with other inflammatory disorders such as rheumatoid arthritis are also at increased risk of depression.
Could inflammatory changes in the brain be one of the main drivers behind our epidemic of depression? And could this explain why antidepressant medications often don't work for people with depression?
This is an exciting new area of research.
In pursuit of the inflammation-depression connection, researchers from Emory University in Atlanta looked at the use of an anti-inflammatory drug called infliximab for the treatment of major depression in people who had not responded to antidepressants. Infliximab, also known as Remicade, is usually given to people with inflammatory disorders such as rheumatoid arthritis, inflammatory bowel disease and psoriasis.
The researchers in the study found that 62 percent of depressed people with high blood levels of C-reactive protein had a reduction in their depression while taking the infliximab, while only 33 percent of those with normal CRP levels noted improvement. This was the first time that a drug specifically targeting inflammation was used to successfully treat depression, and provides some support for the depression-inflammation theory.
This is intriguing data, but drugs such as infliximab are very costly and also carry the risk of significant side effects, so they would not be first-line medications for depression. Fortunately, there are much easier ways to reduce inflammation, including — you guessed it — improving your nutrition and getting regular exercise. In fact, a diet high in healthy foods such as vegetables, fruit and fish — similar to what we call the Mediterranean diet — has been shown to reduce the risk of depression.
A five-year study of 3,500 middle-aged adults published in the British Journal of Psychiatry in 2009 showed that people who ate a diet high in processed foods, including refined carbohydrates, sugary desserts, fried foods and processed meats, had a 58 percent higher risk of depression compared with those who followed a healthy Mediterranean-type diet.
And if you just can't give up those steaks and hamburgers, take heart. Another study from the University of Melbourne in Australia showed that a healthy whole-foods diet, including grass-fed beef, fish, vegetables, fruit and whole grains, reduced the risk of depression. Pastured grass-fed beef, unlike cattle raised in feedlots, is high in healthy omega-3 fatty acids, which play an important role in the health of your brain.
Should you or your loved ones suffer from persistent depression, it's important to see your doctor. But in the meantime, this new research is confirming what some scientists have speculated for years — what we eat and how we take care of ourselves can play a huge role in our mental well-being. And that means less reliance on expensive medications — as well as lower health care costs — for you.
Drs. Kay Judge and Maxine Barish-Wreden are medical directors of Sutter Downtown Integrative Medicine program.
MCT Information Services